Electrochemical systems with ionically conductive and electronically insulating separator

Abstract

Separator systems for electrochemical systems providing electronic, mechanical and chemical properties useful for a variety of applications including electrochemical storage and conversion. Embodiments provide structural, physical and electrostatic attributes useful for managing and controlling dendrite formation and for improving the cycle life and rate capability of electrochemical cells including silicon anode based batteries, air cathode based batteries, redox flow batteries, solid electrolyte based systems, fuel cells, flow batteries and semisolid batteries.

We claim: 
     
       1. An electrochemical cell comprising:
 a solid positive electrode comprising a positive current collector; 
 a solid negative electrode comprising a negative current collector; 
 a solid membrane between the negative electrode and the positive electrode; 
 wherein the solid membrane comprises a solid electrolyte layer; and 
 at least one electronically and ionically conductive layer between the negative electrode and the solid electrolyte layer; 
 wherein the at least one electronically and ionically conductive layer is in direct physical contact with the solid electrolyte layer; and 
 wherein the at least one electronically and ionically conductive layer comprises both a carbon material and at least one metal or metal alloy; 
 wherein the at least one metal or metal alloy comprises a lithium alloy; and 
 wherein said at least one electronically and ionically conductive layer comprises at least one coating on the solid electrolyte layer or on the negative electrode. 
 
     
     
       2. The electrochemical cell of  claim 1 , wherein said at least one coating is not porous. 
     
     
       3. The electrochemical cell of  claim 1 , wherein at least one coating of the electronically and ionically conductive layer is a coating of the at least one metal or metal alloy on the solid electrolyte layer. 
     
     
       4. The electrochemical cell of  claim 1 , wherein at least one coating of the electronically and ionically conductive layer is a coating of both the carbon material and the at least one metal or metal alloy on the solid electrolyte layer. 
     
     
       5. The electrochemical cell of  claim 1 , wherein said at least one electronically and ionically conductive layer has a thickness between 10 nm and 10 μm. 
     
     
       6. The electrochemical cell of  claim 1 , wherein said at least one electronically and ionically conductive layer participates in an electrochemical reaction of the positive electrode or the negative electrode. 
     
     
       7. The electrochemical cell of  claim 1 , wherein said positive electrode comprises a lithiated active material. 
     
     
       8. The electrochemical cell of  claim 7 , wherein the positive electrode comprises a lithiated metal oxide. 
     
     
       9. The electrochemical cell of  claim 1 , wherein the negative electrode comprises a material that undergoes a shape change. 
     
     
       10. The electrochemical cell of  claim 1 , wherein said negative electrode comprises lithium metal and/or a lithium alloy. 
     
     
       11. The electrochemical cell of  claim 1 , wherein said at least one metal or metal alloy comprises silver (Ag). 
     
     
       12. The electrochemical cell of  claim 1  comprising a lithium secondary battery, wherein said lithium secondary battery is a Li-metal battery. 
     
     
       13. The electrochemical cell of  claim 1 , wherein the electrochemical cell is a rechargeable lithium battery comprising a metallic coating material and wherein the metallic coating material comprises silver, aluminum, zinc or a combination thereof. 
     
     
       14. The electrochemical cell of  claim 1 , wherein the at least one electronically and ionically conductive layer does not store and/or deliver energy. 
     
     
       15. The electrochemical cell of  claim 1 , wherein the at least one electronically and ionically conductive layer is configured to reduce one of the positive electrode and the negative electrode. 
     
     
       16. The electrochemical cell of  claim 1 , wherein the at least one metal or metal alloy comprises aluminum. 
     
     
       17. The electrochemical cell of  claim 1 , wherein the at least one electronically and ionically conductive layer further comprises aluminum oxide. 
     
     
       18. The electrochemical cell of  claim 1 , wherein said at least one metal or metal alloy comprises fibers or nanofibers. 
     
     
       19. The electrochemical cell of  claim 1 , wherein said at least one electronically and ionically conductive layer comprises a coating on the negative electrode. 
     
     
       20. The electrochemical cell of  claim 1 , wherein said at least one electronically and ionically conductive layer comprises a coating on the solid electrolyte layer. 
     
     
       21. The electrochemical cell of  claim 1 , wherein at least one coating is porous. 
     
     
       22. The electrochemical cell of  claim 1 , wherein the at least one electronically and ionically conductive layer is in electrical contact with an active positive electrode material or an active negative electrode material; and
 wherein the at least one electronically and ionically conductive layer reduces at least one of the positive electrode and the negative electrode.